Accept a path or file handle in write_scene_list

[jennifferweslowski-design]

Fixes #523

write_scene_list("scenes.csv", scenes) currently raises TypeError: argument 1 must have a "write" method because the path string is passed straight to csv.writer.

This change lets the first argument be a file handle (existing callers) or a str / pathlib.Path. A path is opened with newline="" inside a context manager so the file is closed after writing, which matches the concern on the issue.

Tests cover a StringIO handle, a str path, and a Path. No video fixtures.

I could not run the suite in this environment; the new tests follow the existing _fake_scenes pattern in tests/test_output.py.

[Breakthrough]

Needs formatting w/ ruff but LGTM otherwise! 👍

[jennifferweslowski-design]

After further review of the discussion in #523, I realize this PR takes the opposite direction from the maintainer guidance that callers should pass an already-opened file handle (and use a context manager themselves).

Even though the change is test-covered and received approval, pushing an API that conflicts with the stated design intent is not the right outcome. I'm closing this PR to avoid further review time and noise.

Sorry for the confusion, and thank you for the careful feedback.

[Breakthrough]

Consider keeping this open, there is some existing precedent for allowing this in other libraries.